If you make use of a general website you may only gain access to a few dozen of these puzzles. However, if you go out of your way during the research process you may be able to find a professional puzzle website that is simply dedicated to Sudoku puzzles alone. This will of course provide you with access to a much larger selection to choose from.
When considering these types of websites you should consider the manner in which they offer these puzzles. Do they offer these types of puzzles in a way in which you can print them up so that you can download and make use of them any time you want? Or you may instead want to find a website that offers Girandola Sudoku puzzles or Hoshi Sudoku puzzles that you can actually play and complete online.
This will allow you to use your desktop computer, laptop, or phone so you can entertain yourself for hours any time, even when you do not have access to the internet.Just be aware that many websites that offer these types of puzzles do in fact charge a membership fee in order for you to gain access to their library.